采暖期北京市不同粒径颗粒物16种元素的分布特征研究

Distribution characteristics of 16 elements in particles with different sizes during heating period in Beijing

目的了解采暖期北京市不同粒径颗粒物上16种元素的浓度水平、聚集程度和分布特征。方法于2015年采暖期在北京市使用PSW-8型气溶胶粒度分布采样器和石英滤膜采集大气颗粒物样品,采用重量法测定不同粒径大气颗粒物的浓度,采用微波消解-ICP/MS法测定不同粒径颗粒物中16种元素的浓度。结果不同粒径大气颗粒物浓度及负载的元素浓度均不同,粒径小于2.1μm的颗粒物浓度及其上负载的元素浓度较高。不同元素在不同粒径颗粒物中的富集程度不一致,Pb、Mn和Cu 3种元素在不同粒径单位质量颗粒物中的含量均较高。大气颗粒物中Se、Pb、Cs、Ag、As、Rb、Cd和Bi 8种元素也主要集中在粒径小于2.1μm的颗粒物上,占该元素总浓度的比例均大于60%,而Co、U、V和Sr 4种元素主要集中在粒径大于2.1μm的颗粒物中。结论采暖期北京市大气颗粒物浓度及负载元素浓度较高,不同粒径颗粒物上元素的浓度水平、聚集程度和分布特征有所差异,有必要进一步关注较小粒径颗粒物的人群健康影响研究。

Objective To explore the distribution of 16 elements in atmospheric particles with different sizes during heating period in Beijing. Methods PSW-8 sampler and quartz filter membrane were used to collect atmospheric particles in heating period in Beijing, 2015. The gravimetric method was used to measure the concentration of particles and ICP/MS was used to determine the concentrations of elements. Results The concentrations of particles and elements on different sizes particles were different in Beijing. The concentrations of particles and elements were enriched in particles with diameter of less than 2.1 μm.The enrichment degree of different elements in different particle size was different. The absolute mass value of Pb, Mn and Cu were higher than other elements on different size particles. Se, Pb, Cs, Ag, As, Rb, Cd and Bi were mainly distributed in particles with particle size less than 2.1 μm, and the proportions of total elements were more than 60%, whereas, Co, U, V and Sr were mainly concentrated in the particles larger than 2.1μm. Conclusion The concentrations of airborne particulate matter and load elements in Beijing are higher during heating period, and the concentration level, aggregation degree and distribution characteristics of elements in different particle sizes were different. It is necessary to pay more attention to the health effects of particles with smaller particle size.